Picker International, Inc.

Picker Corporation

Other

Robert J Vagi

Leonard F Plut

Hung Y Wong

David L Leong

A patient is positioned on a patient support (12) and a gantry (16) carrying an x-ray source (10) and a radiation detector assembly (14) are rotated around the subject. The detector assembly includes a video camera (28) which is run in a synchronous mode to generate a first plurality of images at regular temporal intervals T.sub.blanking. Because each image requires a finite time for generation, it is acquired over an interval of arc between a starting angular orientation (A.sub.S .degree., B.sub.S .degree.) and a terminal angular orientation (A.sub.T .degree., B.sub.T .degree.). A position encoder (40) monitors the terminal positions of each of the first series of images. The patient is then injected with a radiographic dye and the gantry is rotated in a reverse direction. A comparator compares the stored terminal angular positions of each forward direction image and the current angular position of the gantry. A trigger circuit (54) triggers an asynchronous mode x-ray exposure controller (50) such that a video image is commenced at each terminal angular orientation. Images generated over substantially the same arc segment are subtracted (66) to form a difference image for storage in a difference image memory (68) and display on a monitor (72).

Rotational angiography dye and mask image acquisition and synchronization

A TV camera (22) generates a low level video signal which represents a sensed image pattern from an image intensifier (18). A preamplifier circuit (24) boosts the low level video signal. The preamplifier is selectively switched between feedback paths (74,76) to select the gain of the preamplifier, and between various filter paths (84,88) to select the bandwidth. Various display processing components such as a digital acquisition system (42) and video tape or video disc recorder (44) are provided to process video signals from the preamplifier circuit. A monitor (26) containing circuitry to generate synchronization signals, to adjust brightness, to adjust images aspect ratio, and to adjust image resolution is provided to convert the video signals into a man readable display. A video switch (40) selectively routes the video signals from the preamplifier to one of the display processing components and from these components to the monitor. The route, the gain, and the bandwidth are controlled by input from a console (30).

Dual bandwidth/gain video preamplifier

A patient (12) is irradiated with x-rays (10) from an x-ray tube (A). X-rays that have passed through a region of interest of the patient are converted to a light image by a phosphor screen (14) on the dome shaped input face (16) of an image intensifier (B). The dome shaped input face causes the output optical image (20) of the image intensifier to be distorted with pin cushion distortion. The sweep pattern of the electron beam of a video pick up tube (24) of a video camera (C) is controlled by deflection plates (26a, 26b, 26c, 26d). A sweep control circuit (D) alters the sweep pattern such that electronic image representations generated by the video camera are distorted in a manner that is complementary to and cancels the image intensifier tube distortion. In this manner, the two distortions cancel and a man-readable image (28) displayed on a video monitor (22) is substantially distortion-free. The sweep control circuit alters conventional vertical sweep control voltage ramps (V) and horizontal control voltage ramps (H) by adding third order, parabolic terms:

Geometric distortion-free image intensifier system

An X-ray spot filmer is disclosed including a system for cyclically shifting a grid assembly interposed between an X-ray source and a film cassette. The system comprises an electrically energizable grid assembly actuator and an actuator controller for energizing the actuator to cyclically shift the grid assembly. The actuator controller includes actuator energizing output circuitry effective to govern the direction and speed of operation of the actuator in response to a control signal and control signal generator circuitry for producing control signals effective to govern operation of the output circuitry including an oscillator for producing a cyclically varying control signal which causes cyclic grid assembly shifting.

Radiation imaging system with cyclically shiftable grid assembly

A medical diagnostic system and method is disclosed for producing television and laser light images of penetrative radiation patterns from a subject as converted to visible light images by an image tube. The apparatus includes a penetrative radiation source for directing radiation through a subject, an image tube for receiving that radiation and in response producing a visible nonlaser light image corresponding to the pattern of such radiation impinging upon the image tube. The apparatus also includes a television camera for viewing the image tube output. A laser beam recorder receives a composite television signal from the television camera and in response produces a laser light image corresponding to the image viewed by the television camera. The laser beam recorder produces a laser beam. The recorder includes apparatus for deflecting the beam horizontally and vertically with a mechanical scanner, in accordance with the synchronization signals of the television composite to produce an image raster with the laser light. The laser beam recorder also amplitude modulates the beam with the analog video portion of the television signal to produce a laser image. A novel control circuit controls the operation of the mechanical scanner, over an excursion, while inhibiting undesirable harmonic oscillation at the end of the excursion.

Deflector control circuit

A radiation imaging system and method is disclosed for producing an enhanced television image of diagnostic quality from a light image produced by a common image tube and corresponding to a pattern of penetrative radiation from a subject. A source directs radiation such as X-rays through the subject and the image tube converts the emergent radiation pattern to a corresponding visible light image at an output phosphor. A television apparatus including an image isocon pickup tube views the output light image at a tube input face by way of a lens assembly and converts the light image to electrical, including video signals. A television monitor reconverts the electrical signals to a visible television image of enhanced quality representing the pattern of radiation from the subject. The television monitor includes an improved cathode ray tube with a planar output face, a small focal spot, and improved phosphor.

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Broadview Heights, OH, United States of America

Robert J Vagi